POS0162 HOW ACCURATELY CAN WE IDENTIFY RHEUMATOID ARTHRITIS BY ICD-10 CODES? A LINKAGE OF CROSS-SECTIONAL SURVEY DATA WITH CLAIMS DATA
Authors: J. Callhoff, K. Albrecht, U. Marschall, F. Hoffmann
Journal: Annals of the Rheumatic Diseases (2022)

Background Claims data from health insurance companies are a valuable source in health services research to provide insights on health care provision for an unselected patient collective. However, the available ICD-10 diagnoses have been collected for billing purposes and their validity is not clear. Objectives The aim of this analysis was to assess the positive predictive values (PPV) of a ICD-10 diagnosis of rheumatoid arthritis (RA) and additional criteria (specific medication, measurement of inflammatory markers, contact to a rheumatologist) in German claims data using patient-reported confirmed diagnosis as reference/gold standard. Methods Within the PROCLAIR project (Linking Patient-Reported Outcomes with CLAims data for health services research In Rheumatology), data from a large German statutory health insurance with 6.6 million persons aged 18 to 79 were used. We identified a random sample of persons for which an ICD-10 code for RA (M05/M06) was available in at least two quarters in outpatient care. The sample was stratified for age (18 to 49, 50 to 64, 65 to 79 years), sex and seropositive (M05)/ seronegative RA (M06). Persons were asked to confirm their RA diagnosis (“What does your attending physician call the disease you are suffering from?”) with answer options “chronic polyarthritis”, “rheumatoid arthritis”, “rheumatism of the joints” “other (please specify)”. The answer was used as the gold standard for RA diagnosis. Analyses were weighted to represent the total RA population of the database. Patient-reported information was linked to the claims data given patient consent. PPVs (% of confirmed RA diagnosis) were calculated for ICD-10-diagnosis or additional examination of inflammatory markers (erythrocyte sedimentation rate/C-reactive protein), prescription of specific medication (disease-modifying anti-rheumatic drugs, non-steroidal anti-rheumatic drugs and glucocorticoids) and contact to a rheumatologist, in the respective year. Results We contacted 6,193 persons with a claims diagnosis of RA. Of these 3,184 responding (51%), N=2,535 (81%) confirmed that they had RA. PPVs were 81% for ICD-10 only, 94% in M05 and 76% in M06. When additional criteria were taken into account, PPVs increased to 82% (measure of inflammatory markers), 85% (rheumatologist) and 89% (medication), respectively (Figure 1). However, PPVs ranged from 72% to 76% even if the additional criteria were not fulfilled. PPVs were lowest in men aged 18-49 years and relatively stable among women of all age groups. Figure 1. Conclusion The ICD-10 codes M05 and (less optimal) M06 have high PPVs and are therefore feasible to identify RA in claims data. The prerequisite of specific medication seems to be the most useful one in identifying RA. Acknowledgements Supported by the Federal Ministry of Education and Research (grants 01EC1405 and 01EC1902A). Disclosure of Interests Johanna Callhoff Paid instructor for: Rheumatologische Fortbildungsakademie GmbH, Grant/research support from: Abbvie, AstraZeneca, BMS, GSK, Galapagos, Lilly, Medac, MSD, Pfizer, Sanofi, UCB, Katinka Albrecht: None declared, Ursula Marschall Employee of: Employee of BARMER, Falk Hoffmann: None declared